Wafer processing method

1. A wafer processing method for dividing a wafer having a diameter of at least about 450 mm into a plurality of individual devices along a plurality of division lines extending in a first direction on a front side of said wafer and a plurality of division lines extending in a second direction perpendicular to said first direction on the front side of said wafer, said individual devices being respectively formed in a plurality of regions partitioned by said division lines extending in said first direction and said division lines extending in said second direction, said wafer processing method comprising: a wafer quarter generating step of cutting said wafer along said division line extending in said first direction through the center of said wafer and along said division line extending in said second direction through the center of said wafer, thereby generating four sectorial wafer quarters; a holding step of holding each of said wafer quarters on a chuck table having a sectorial suction holding portion, said chuck table configured for holding a wafer with a diameter no greater than 300 mm; a groove forming step of forming a plurality of grooves on the front side of each wafer quarter along all of said division lines extending in said first direction and along all of said division lines extending in said second direction after performing said wafer quarter generating step, each groove having a depth corresponding to a finished thickness of each device; a protective member providing step of providing a protective member on a front side of each wafer quarter after performing said groove forming step; and a wafer quarter dividing step of holding said wafer quarter through said protective member on a chuck table of a grinding apparatus in the condition where a back side of said wafer quarter is exposed after performing said protective member providing step and next grinding the back side of said wafer quarter to reduce the thickness of said wafer quarter to said finished thickness until said grooves are exposed to the back side of said wafer quarter, thereby dividing said wafer quarter into said individual devices, whereby said at least about 450 mm wafer exceeds a wafer diameter size that can be held on said chuck table configured for holding a wafer with a diameter no greater than 300 mm.

2. The wafer processing method according to claim 1 , further comprising a frame providing step of preparing an annular frame having an opening capable of accommodating said wafer quarter after performing said wafer quarter dividing step, next placing said wafer quarter in said opening of said annular frame, next attaching an adhesive tape to said annular frame and the back side of said wafer quarter, and next peeling said protective member from the front side of said wafer quarter, thereby supporting said wafer quarter through said adhesive tape to said annular frame.